How to make a 23 cm band vertical antenna with 10 dB gain.

Рет қаралды 11,422

Күн бұрын

Step by step construction from cutting the coax sections to the correct length, soldering together then potting. Measuring the SWR and on air testing. From a New Zealand amateur radio article with the link at the end.

Пікірлер: 34

@gammaleader96 6 ай бұрын

I built one of these antennas from RG393. (Of course I modified the dimensions accordingly) Thanks for the video it helped me to find a good way of building the elements.

@Jonny10001 6 ай бұрын

Thanks for your comment,👍

@zaperfan 2 жыл бұрын

It's great to see homemade stuff work like a charm, it's an old post now, but I found it. Very informative thanks you done a fantastic job

@Jonny10001 2 жыл бұрын

When I began construction I didn’t know for sure that it would work, just trusting the original article. Thanks for the compliment.

@kiweekeith Жыл бұрын

Thanks for a Brilliant vidclip, Super interesting .... Best to All from ChCh, NZ .... Cheers .... WR2451, KK2451

@Jonny10001 Жыл бұрын

Thanks for the compliment on the video

@Bazzawombat 2 жыл бұрын

Hi John, thought I recognized the voice, thanks for presenting the video, barry, VK2FP

@Jonny10001 2 жыл бұрын

Hi Barry, the music is a bit loud so i’m going to upload a version 2, thanks for the comment, John

@kriswoolsey8886 2 жыл бұрын

Great video ! No problem with audio on my android phone . Thanks for sharing & 73

@KennethLubin Жыл бұрын

Thanks for sharing. Great job. 👍

@Jonny10001 Жыл бұрын

Thanks for the compliment 🤗

@Jonny10001 3 жыл бұрын

Thanks for the constructive feedback, the music is a bit loud compared to the commentary.

@SimonShaws 2 жыл бұрын

One of best videos on collinear. Also love the singlet n shorts. My preferred work gear also. Assume you are in Australia? Perth here.

@Jonny10001 2 жыл бұрын

Hi Simon, thanks for the compliment. I am located in Sydney and a lot of the video was shot on hot summer nights. Had to cut out the stubby of beer in the background!!

@vk2jy391 Жыл бұрын

Hi John What size conduct I did you use and were did your but the jointing resin.

@Jonny10001 2 жыл бұрын

The link to the original article has become unreadable. I have scanned in my copy of the plans and have uploaded as a PDF to Google Drive:-drive.google.com/drive/folders/1uTDLnGHStLtSZtjEc7XKe_ERZeFjlOXX?usp=sharing

@5Perf65mm Жыл бұрын

Many thanks for sharing the link

@Jonny10001 Жыл бұрын

@@5Perf65mm Your welcome, mine has been up a few years now and working as good as the day I installed it.

@ramjet4025 2 жыл бұрын

Jonny, can you please post a CLEAR copy of this PDF article? all the copies on line on the ZL sites have the key page in terrible resolution that is a copy of a copy of a copy till its useless.

@Aleziss 3 жыл бұрын

please stop using music... difficult to understand you talking and it add nothing to your awesome video...

@9PAT508 2 жыл бұрын

how do i calculate the lenght for 151.820 MHz thanks

@Jonny10001 2 жыл бұрын

You have to scale the dimensions up by a factor of 8.4 but it then becomes to big to be practical. Have a look at helical filter designs, they suite the lower frequencies better.

@ulrichm.12 2 жыл бұрын

Hi Jonny, that's just the DIY-Project, I was looking for. I want to build a LoRa-WAN-Antenna for Europe tuned for 868 MHz and approximately 9 dB. Buying is too expensive and I want to tune it perfectly to 868 MHz. Would you please tell me the exact measurements of the coax pieces or the way to calculate it for my own. And : What effect has the piece of copper at the bottom and in what distance it has to be soldered ? Many thanks, Ulrich from Germany

@Jonny10001 2 жыл бұрын

You can calculate the element length in inches using the formula 5904 divided by the desired resonant frequency of the antenna, times the velocity factor of the coaxial cable. I used RG-213 with a velocity factor of 0.66 or 66%. The copper tube is a coaxial sleeve balun to prevent RF travelling back down the coax braid. It should be 1/4 wavelength long and connected 1/4 wavelength down from where the feed line attaches to the first element. Here is a link to the original article. zl2vh.org.nz/assets/pdf/other/23-cm-band-fm-repeater-specs-rev-2014.pdf

@ulrichm.12 2 жыл бұрын

Jonny, thanks for your answer. I just calculated a bit and recognized, that the antenna will get rather tall (90,2 cm). Would it be possible, to make the 1/2-wavelength-pieces only 1/4 in length and therefore the 1/4-pieces in to 1/8 length ? Would make the antenna only half long (45,1 cm). But what is with the frequency (868 MHz) ? Will it fit also ? What do you mean ?

@Jonny10001 2 жыл бұрын

Hi Ulrich, it’s a physics thing, it won’t work if it’s not a half wave length. You could make a ground plane antenna, four 45 degree sloping 1/4 wave radials and a 1/4 wave vertical. Not as much gain as the co-linear but still good.

@ulrichm.12 2 жыл бұрын

@@Jonny10001 Thanks, I already built a ground plane antenna. Works fine, but I want more gain. Okay, then now I will start my project with your co-linear. I'm curious about the efficiency and the results.

@kuizatz Жыл бұрын

Which type of coax did you use between the ant and the shack please? and how long?

@Jonny10001 Жыл бұрын

Hi John, I used 9913 coax, about 10 meters from the antenna to the receiver. The 23cm band seems to propagate much better then most people realise. I was was able to receive the distant beacon with the antenna inside the shack when testing even though there was a brick wall in front and a metal roof above!

@kuizatz Жыл бұрын

@@Jonny10001 Thanks very much for the reply!.. Ok I thought the coax would be something like that. I did a lot of S-Band work when there was such a thing as an Molniya orbiting AMSAT and pretty much 9913 was a min so I have some about the place. Yes 23cm interesting band, have been building a UHF tripler using a triode and can trigger a repeater with the output connected directly to a big fat dummy load, go figure. Great video thanx again

@ramjet4025 2 жыл бұрын

at 7:20 you talk about "a specific distance" that you solder down here. In this video, you miss all the key dimensions that make the difference. You incorrectly make assumptions that the view has the same resources as you and that's incorrect.. You missed a teaching moment in describing what you were doing and the measurements and how you came about those measurments.

@Jonny10001 2 жыл бұрын

I didn’t design the antenna I built it from an online article by a ZL group which shows all dimensions in detail. My aim in the video was to show construction methods and give tips to aid completion. I don’t know why the original article has become hard to read but I have uploaded my copy to Google Drive, see link.